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Sub‐ppm determination of Hg and Cr in water: Cr speciation
Author(s) -
Leyva D.,
Estévez J.,
Montero A.,
Pupo I.
Publication year - 2007
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.983
Subject(s) - coprecipitation , chromium , mercury (programming language) , chemistry , environmental chemistry , detection limit , analytical chemistry (journal) , inorganic chemistry , chromatography , organic chemistry , computer science , programming language
Abstract A sensitive and alternative analytical procedure for the determination of chromium and mercury content in natural waters by coprecipitation with APDC and determination using an absolute thin layer EDXRF method is described. The use of 109 Cd and 238 Pu annular radioisotope sources, the influence of the chromium oxidation states and the elemental concentration were studied. At pH 4, 100% recovery was found for mercury. The coprecipitation of Cr(VI) was not quantitative (75%) but constant for the selected concentration range (5–100 µg/l). On the other hand, Cr(III) did not precipitate at the same pH. The relative standard deviations (RSD) were lower than 9.0% for mercury (10 µg/l) and 5.0% for chromium (50 µg/l). The detection limits (DLs) for mercury and chromium were 0.4 and 0.6 µg/l when the 238 Pu source was employed. Nevertheless, higher DL values were achieved using 109 Cd (0.6 and 3.3 µg/l). The proposed method was applied to the analysis of surface water samples. An alternative and simple chromium speciation procedure without chemical separation of Cr species is recommended. Copyright © 2007 John Wiley & Sons, Ltd.